P1628: ALLOIMMUNIZATION DURING ASSISTED REPRODUCTIVE TECNOLOGY: CASE REPORT OF A PREGNANCY WITH IRREGULAR ANTIBODIES PROBABILY RELATED TO EGG DONOR ANTIGEN.
Authors: M. Rolli, V. Lara, L. Bensi, P. Artusi, M. Savarino, G. B. Ceccherelli, D. Venturelli
Journal: HemaSphere (2022)

Background: Alloimmunization is a well known complication during pregnancy. It consists in an immune response of the mother against non-self antigens expressed by the fetus, which derive from the male partner, and its manifestation is an hemolytic disease of the fetus and newborn (HDFN). The most common antigen involved in alloimmunization came from the AB0 group and affect 15% to 25% of all pregnancies. However, the response caused by AB0 incompatibly is modest most likely due to the expression of AB0 blood type antigen in several organs. Other red cell antigens have been implicated in the HDFN; the Rh(D) antigen is the most immunogenic and the main cause of HDFN because the antigen is well expressed on the surface of the erythrocytes in the fetus. Previously, HDFN was known to cause fetal death in 1% of all pregnancies; with the advent of immunoprophylactic therapies, HDFN is currently well managed with fewer complications. In Italy, RBC iantibody screenings are typically performed at first and third trimester of pregnancy. Affected women are followed up to ensure the timely identification of those antibodies who require therapeutic interventions to prevent perinatal morbidity and mortality. The italian guidelines aim to direct these women to third-level centers where management protocols are shared by Immuno-hematology and Obstetrics Units in order to monitor the pregnancy with laboratory tests and clinical interventions. Aims: Identification of risk factor for alloimmunization during pregnancy Methods: Blood group, undirect and direct antiglobulin test during prregnancy mounthly based. After delivery blood group and DAT on Newborn Results: We report a case of alloimmunization during pregnancy of a woman that underwent a medically assisted procreation with egg donation. The subject, in apparently good health, had no chronic pathologies and was not taking medications. Her blood group was B Neg ccdee kk and the partner was 0 Pos CcDee Kk During the last triemster of the pregnancy, the woman developed alloimmunization towards many antigens of different blood systems,Rh (anti-D, antiC, anti-E), and the Kell (anti-Kell) systems. at low titers At week 37 of the pregnancy, she was admitted to the hospital for obstetrical problems and delivery was induced without clinical complications, neither for her nor for the fetus. Newborn blood group was 0 Pos CcDee Kk and Direct antiglobulin test was positive (++++). Anti-RHD and Kell antibodies were identified after elution. Additional studies are underway to characterize the egg donor RBC Phenotype to verify the presence of E antigen Summary/Conclusion: Alloimmunization during pregnancy is a condition caused by a response of the mother to paternal antigenes exhibited by the fetus and can be monitored with standard laboratory and clinical approaches However, the possibility to carry out pregnancies with egg donor that has a different RBC antigen profile of the mother open a new immuno-hematological scenarios previously not pointed. This could lead to potentially increased risk for the mother and the newborn.